1. Field of the Invention
This invention relates in general to a method of forming laminates of flexible material, and in particular to a method of forming a cushioning layer on a water ski foot support.
2. Description of the Prior Art
Water skis have a boot binding for retaining one's foot to the ski. In addition, with slalom skis, wherein the skier uses a single ski, a second boot binding will be located to the rear of the main binding for retaining the other foot. The main boot binding has a forward support of flexible vinyl or rubber-like material, into which the user slides the forward portion of his foot. A heel support of similar material slides along the ski board to adjust for a tight fit. The rear boot binding on the slalom ski is similar to the forward support of the main boot binding.
To avoid tearing, the vinyl supports must be strong and tough. However, a strong vinyl backing is somewhat stiff and smooth, thus tends to chafe a user's foot and allow slipping. For comfort, one prior art support uses a laminate having a vinyl backing for strength and a cushioning layer for comfort. The preferred cushioning layer used is a foamable polyvinyl chloride plastisol resin that is soft and resists slipping.
In the prior art manufacturing method, a metal casting mold is used. First the vinyl backing material is poured into the mold and allowed to set or thicken to a certain extent. Then the plastisol resin is poured in at room temperature. The mold containing the two layers is placed in an oven. The oven causes the plastisol resin to change into a solid, soft cushion. After curing, the support is removed from the mold and mounted to the ski.
One disadvantage of this prior art method is that a casting mold is in use for several minutes for each support. For large scale production, numerous expensive casting molds must be used.